I am reworking my Mythic Ireland material to use in a Celtos: Realms of Goria campaign. All of the player characters will initially be Gaels, and most of these folks just don't wear much armor. I want the characters to have viable reasons for not wearing maximum armor--specifically by providing them with benefits tied to the pseudo-Celtic background of the world. Naturally, I found myself compelled to borrow from SK to achieve this. Here is what I have...

III. Characters, Customs, and Traditions
All beginning characters are Gael heroes; therefore, each automatically begins with one or two Geasa—either one major or two minor—and a racial Edge called Earth Fury. The Geasa offset the cost of this Edge, leaving a beginning Gael to select up to four additional points in Hindrances, all of which may be spent as usual. Furthermore, Gaels are human and receive one free Edge. All other aspects of character generation are as outlined in the Savage Worlds rulebook.

Earth Fury (Racial)
Requirements: Gael, Wildcard
The Gaels are the children of Anu, and as such they can draw from her strength in times of need. Any time a Gael Wildcard spends a Bennie in combat, his player should roll a separate d6. On a roll of 5-6, the character is filled with the elemental power of the earth. His body grows, warps, and spasms as he struggles to contain this supernatural energy, and he gains the roll of a d6 to all trait and damage rolls for his next three actions. Earth Fury kicks in immediately and even adds to the very roll for which the Bennie was spent. When three actions have been effected, the character’s body returns to normal and the Earth Fury subsides. If a character is wearing armor when the Earth Fury strikes, he immediately takes damage—a d6 for each plus of armor protection (only use the highest value worn). For example, a character who is wearing a chain pants for +2 Toughness and a breastplate for +3 Toughness would take 3d6 damage during a bout of Earth Fury. Note: A character enchanted with an Oak Harness spell will not take damage when overcome by Earth Fury.

Earth Rage (Racial)
Requirements: Heroic, Earth Fury, Wildcard, Spirit d6+
A character with the Earth Rage Edge has a special affinity with Anu and the power of the earth. Once per game session, he is able to spend a Bennie and automatically trigger his Earth Fury, instead of rolling to see if it is triggered. Furthermore, the benefit gained from his Earth Fury is rolled on a d8!

Skyclad
Many Gaels believe they must not separate themselves from their gods or diminish their valor by wearing armor; they see any reliance upon such trappings as a form of cowardice. Fortunately, Anu and Lamfahda bless warriors who go into battle skyclad—completely naked but painted by the druids with woad symbols that dedicate these champions to their deities. A skyclad Wildcard character receives +1 Bennie the moment he enters combat and will benefit from Earth Fury on a d6 roll of 4-6!

Taking Heads
Warriors often take the heads of slain foes and carry them as trophies (usually strung around their horses’ necks), nail them to the fronts of their houses, or “pickle” them in cedar oil and store them in special chests for later display. This is not only one of the easiest ways for a warrior to be recognized for his prowess, it can also improve his position in the afterlife! Amongst the Gaels the human head is revered above all else, since the head is considered to be the dwelling place of the soul and the center of emotions and life. Therefore, capturing a head means that one has captured the soul of an opponent, and when a Gael dies, the dead whom he has collected will serve him as slaves for all eternity! Not surprisingly, many druidic rites involve the severed heads of enemies, and the tribe’s priests often aid their warriors in gaining the spirit and courage of slain enemies through elaborate ceremonies involving these gory prizes. Particularly powerful druids may even be able to restore senses to a severed head so that it will cry out when its owner’s enemies approach! A Gael character who takes an equal or superior foe’s head in battle immediately gains +1 Bennie.

Please let me know what you think--I definitely trust in our collective intelligence on such matters

I'm not quite so sure about the damage taken due to armour when the Earth Fury triggers though, why not reduce the chance or fury to 1 in 6 and impose a Charisma penalty (1 per point of Armour would be easy to remember) to those wearing armour

Borrowing the Fame rules from Pirates might be a god idea for this setting too
Also I'd allow any character to add their Charisma to their Intimidation rolls (as the Reputation Edge)

In fact I'd try to make Reputation/Charisma very important.
What about making Charisma a bonus to command radius
Bards might be able to temporarily enhance a Rep with a good performance (a trapping of the Boost Trait Power?)

For a slightly different take on Steelbrok's idea, why not make the roll to activate Earth Fury something like (3 + number of points of armor) or higher on the d6. Thus, for those with no armor, it activates on 3-6, but wth wearing a breastplate would reduce the chance to just activating on a 6.